What is Open Rate?

Open rate is the percentage of delivered emails that recipients open, calculated as opens divided by delivered messages. It's a rough gauge of two things: how compelling your subject line and sender name are, and whether your emails are actually landing in the inbox rather than spam.

Open rate has become a less reliable metric since privacy features like Apple's Mail Privacy Protection began pre-loading images and inflating open counts. Because of this, most experienced teams treat open rate as a directional signal for deliverability and subject-line testing, and lean on reply rate and booked meetings as the metrics that actually reflect results.

A sudden drop in open rate is still a useful early warning that your sender reputation or deliverability may be degrading.